
My own dog was kept in an outbuilding of sorts ( hard to explain, it was connected to the house, by way of the utility room.. so two doors away from the kitchen.) as a pup. When I picked him up at 9 weeks he was still in there with other puppies but had no adult dogs apart from his Mum. As a young pup he was obsessed with dogs because I don't think he'd mixed with any other than pups of his own age and his Mum, and playing with other dogs in the same way he would his littermates was obviously not acceptable.
I didn't think of this aspect until much later in his life when he lost his 'puppy license' and still tried to play like a puppy for the most part. After a number of incidents with other dogs telling him off good and proper, he is now slightly on the nervous side around strange dogs and I do wonder how much of it was down to the way he was kenneled.
That being said, I have met tons of pups that have been home reared but still don't come across any other dogs and I assume they would have similar attitudes to other dogs at a young age.
After many months on a longline teaching him a solid re-call, he is now happy to leave other dogs alone but he will still say 'hi' if he thinks he can get away with it.
Overall, I think it isn't as black and white as kennel = bad, home = good. Puppy buyers should look at the bigger picture of what socialisation the breeder does and how many dogs are in there etc etc. Frankly, a badly socialised pup is going to be badly socialised in early because of the breeder. It is down to the breeder and not down to the where the breeder chooses to keep their dogs. I would happily take on a kenneled pup/dog as long as other socialisation had been done and they weren't just confined to a kennel/shed for the first 8 weeks of their lives.